Described herein are phase change ink compositions comprising an ink vehicle and at least one pigment, wherein the ink composition is substantially solid at room temperature and includes at least one dispersant and at least one synergist. The dispersant and synergist allow the pigment to be well dispersed in the solid phase change ink composition without adversely affecting the hardness of the ink. The phase change inks are suitable for ink jet printing processes.
Advantages achieved by the phase change inks herein include that the use of at least one dispersant and at least one synergist results in very stable inks, as determined by the measurement of particle size after subjecting the inks to high temperatures, for example 100° C., for extended periods of time, for example 1 week. Furthermore, the amount of dispersant, in particular dispersants that are liquid or paste-like at room temperature, required to stabilize the pigment in the ink can be reduced without sacrificing ink stability, thereby also achieving a reduction in the tackiness of the ink during processing and on image prints from the subsequent printed ink.